On Mon, 12 Jul 2004 07:31:01 GMT, Richard Clark
wrote:
[Earlier stuff snipped]
|
|Following up with a series of 2 wavelength measurements, it is
|interesting to note that of the series of 19 tests, fully 13 of them
|evidenced HIGHER gain than those from the 20 wavelength series of
|measurements.
|
|The step from 2 wavelength to 5 wavelength showed gains consistent
|with doubling the length of the antenna size for many separations
|(e.g. 3dB gain, or thereabout). However, it appears that beyond 5
|wavelengths (considering my next cardinal point was a doubling to 10
|wavelengths) no further gain was observed as a general characteristic.
|
|If I were to judge this at the 180 degree spread and compare against
|ALL other designs; then the absolute greatest gain for a V design was
|observed to be slightly less than 4dB. In fact, the 2, 5, 10, and 20
|wavelength designs configured as simple dipoles barely differed one
|from the other (1dB at most, and typically 9.9dBi).


I must confess that I've tried to follow your path but clearly I'm
lost.

May I suggest that analysis at "180 degree spread", which I take to
mean a dipole, has no relationship to a vee configuration, other than
the wire length. If you will take each leg length and vary the apex
angle to the optimum, you will (should) find that the gain *does*
continue to increase with increased leg length, albeit at a
sub-proportional rate.

For each leg length there is an optimal apex angle. Leaving the angle
fixed and varying the length is *not* a fair test of gain vs. length.

Here are the results I obtained from a quick MultiNEC (NEC-2)
analysis. This at 144 Mhz with height = 20', Sommerfeld Gnd, with
average dirt. #12 AWG Al wire, 20 segments/WL, elevation angle = 4
deg. Source on the middle of a short (3 segment) wire.

Len. (WL) Ang. (deg) Gain (dBi)

10.200 30 19.84
20.193 20 21.97
30.188 16 23.06
40.185 14 23.70
50.182 12 24.10

These data seem resonable and consistant with my expectations.

Wes